Adsorption and oxidation of NH3 over V2O5/AC surface

V2O5/AC has been reported to be active for selective catalytic reduction (SCR) of NO with NH3 at around 200 °C and resistant to SO2 deactivation. To elucidate its SCR mechanism, adsorption and oxidation of NH3 over V2O5/AC are studied in this paper using TG, MS and DRIFTS techniques. It is found that the adsorption and oxidation of NH3 take place mainly at VO bond of V2O5. A higher V2O5 loading results in more NH3 adsorption on the catalyst. V2O5 contains both Brϕnsted and Lewis acid sites; NH4+ on Brϕnsted acid sites is less stable and easier to be oxidized than NH3 on Lewis acid sites. Gaseous O2 promotes interaction of NH3 with AC and oxidation of NH3 over V2O5/AC. NH3 is oxidized into NH2 and acylamide structures and then to isocyanate species, which is an intermediate for N2 formation.